Abstract: A lamp circuit assembly mounted in a hollow handle of a screwdriver and partially projecting out of a hole of an end cap at one end of the handle and controlled to give light, including a LED mount having two opposite contacts, a plurality of light emitting diodes connected to the contacts of the LED mount, two battery cells reversely connected to the contacts of the LED mount, and a push button switch connected to the battery cells at one end opposite to the LED mount and pressed to turn on/off the LEDs.

Abstract: An output buffer with a controlled high logic state prevents the output voltage from increasing when the supply voltage, Vcc, increases. A fast low-to-high logic transition is achieved by using a pumping circuit to improve the low-to-high transition rate. However, when the Vcc voltage rises past a threshold value, the pumping circuit will only be enabled during a portion of the transition time. This prevents the output level from increasing beyond its nominal value. Because the output voltage is controlled, the high-to-low transition time is reduced and the ground bounce or noise generated by the output signal is minimized.